Natural Selection Powerpoint Download

Transcript
Artificial Selection Examples
Evolution by Natural
Selection
Essential Question
How does evidence support the claim that
the process of evolution by natural
selection primarily results from 4 factors?
Factor 1
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Organisms must be able to reproduce to increase
population size, however…
For any species, population sizes would increase
exponentially if all individuals that are born
survived and reproduced successfully
Factor 2
Heritable, genetic
variation is due to:
■ Random mutations
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• not always bad!
■ Sexual
reproduction
• think meiosis, Punnett squares
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Traits are inherited by
chance
Adaptation – an
inherited trait that gives
you an advantage in the
environment
Factor 3
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Resources are limited so organisms must
compete for them
Resources include: food, water,
space/shelter, sunlight (plants), mates
Factor 4
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Organisms with traits
better suited to the
environment are more
likely to survive and
reproduce than organisms
less suited to the
environment
Favorable characteristics
accumulate over
generations
Natural Selection
Natural Selection Leads To Diversity
Click to watch this video clip
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5 Fingers of Evolution